1. Field of the Invention
The present invention relates to a method for preparing biphenylphosphonate compound, and is particularly about the production of biphenylphosphonate compound used as a type of flame retardant.
2. Description of the Related Prior Art
Biphenylphosphonate compound were commonly used as a type of flame retardant for processing plastic products manufactured at high temperature. The most well-known flame retardant phosphate compound is tetraphenyl resorcinol diphosphate (RDP), which could be prepared by various methods, such as esterification using magnesium chloride, zinc chloride, or aluminum trichloride as catalyst. But the low selectivity and mono-condensed side products have been the downside of RDP compound.
The inventor of the present invention had disclosed a preparation method for a type of aromatic phosphonate compound under Taiwan Patent No. 143,835, but the reaction yield was excessively low. To simplify the reaction procedure and improve the reaction yield, the present invention has come out with better method for the production of biphenyl-phosphonate compound.